582 
WOUNDS PENETRATING INTO THE CHEST. 
The lungs were collapsed, condensed, and contained a great 
quantity of blood of a deep black colour, which reddened when 
it had been exposed to the air a little while. The bronchi were 
filled with liquid spume. 
The other horses which died after the same kind of experiment 
lived longer than this mare. The lesions which were found after 
death were similar to those here described; but we have selected 
the mare, in order to prove the fatal effect of the introduction of 
air into the chest, even when there is no eff usion of blood. The 
presence of air alone can effect a great alteration in the pleural 
serosity, as we have proved by numerous experiments. In this 
case the natural fluid of the pleural cavity becomes thickened, 
grey, decomposed, and, in a word, it undergoes the same change 
as if it had been exposed in a vase to the free action of atmo¬ 
spheric air. Thus the presence of air in the chest, and especially 
when continued for a certain time, is dangerous, not only from 
the physical action of the air, but from the alteration which it 
produces in the serosity of the pleurae whether directly or indi¬ 
rectly. 
4. Simple wounds in the walls of the thorax , with bleeding 
from an intercostal artery , and the effusion of blood in the pleural 
cavity , but without the introduction of air into the chest . 
All the conditions which this experiment, strictly conducted, 
would exact could not be fulfilled, for it is impossible to find out 
an intercostal artery, and divide it, and direct the jet of blood 
into the chest without a certain quantity of air introducing it¬ 
self with the blood into the pleural cavity : nevertheless, by using 
a great deal of caution, we may prevent the admission of a quan¬ 
tity sufficient to disturb the respiratory function in any consider¬ 
able degree. In order to attain this object, we first discover an 
intercostal artery, and we lay it bare, and dissect it from its 
attachments for a length of about six or eight centimetres (2i 
or 3 inches). We then tie the superior part of it, and having 
cut it at the inferior part, we search for the pleura; we puncture 
it, and introduce the free extremity of the artery into the opening, 
taking care to place our thumb upon the wound as soon as we 
have turned the artery into the chest, in order to prevent the air 
from penetrating into the pleural sac. This precaution, which 
does not perhaps absolutely exclude all air, yet gives passage to 
so little a quantity, that the result of the experiment is not at all 
interfered with. 
As soon as the artery is introduced into the chest, we loosen 
the ligature which compressed it superiorly, and suffer the blood 
to run into the chest. We then tighten the ligature anew, with¬ 
draw it from the chest, and pass a suture, a bourdonnets (a small 
